Extension-rule.



aHo'mw J G. K. DENMAN & W. H. MURPHY.

EXTENSION RULE.

APPLIOATION FILED DBO.20,1907.

Qm o 9 Q .Q N. .m W 0 w ii i a 9 rfi UNITED STATES PATENT OFFICE.

cursors) K. DENMAN am) WILLIAM nanvar MURPHY, or GREELEY, ooromnoemanates-am. w i

No. scopes.

Specification of Letters Patent.

' Patented Ian. 5, 190a.

To all whom it may concern:

Be it known that we, CLIFFORD K. DEN- MAN and WILLIAM HARVEY MURPHY, both citizens of the United States, residing at Greeley, in the county of Weld and State of Colorado, have invented certain new and useful Improvements in Extension-Rules;'

and we do declare the followin to be a full,

clear,'and exact descri tion of t e invention, such as will enable ot ers skilled inthe art The device is especially adapted for measuring distances between walls since it is only necessary to place the instrument in a position between the two'walls and then extend it until its extremities engage the walls.

The device is composed of an desired number of members each of whic may be of any desired length. The various members are slidably connected the one with the other and are so arranged that when the device is not in use it may be adjusted to' occupy but little space whereby it may be easily placed within a chest or other race tacle for carpenters tools or even carried 111 the ocket. While these members may be slida ly connectedxin an suitable manner, we have illustrated them In the drawing connected by dove-tailed tongues and grooves. What we will term the top member of the device is plain or rooved, its lower surface being provide with a dove-tailed tongue adapted to fit a counterpart groove formed in the to of its engaging section. The bottom of t c section havin the top dove-tailed groove is in turn provi ed with a dove-tailed tongue engaging a counterpart groove in the member next below and so on 'untilthe desired number of members are obtained. The bottom member has its lower surface plain. All of the members except the bottom member are provided with fastening devices as set' screws for locking the members in the desired position of adjus'tment after ,a measurement has been obtained. Each of the devices except the lowermost is also provided with a sprin catch adapted to engage recesses forme scale.

in the adjacent members when the device is full extended.

aving briefly outlined our improved.

device, we will proceed to describe the saine in detail reference being made to the accompanying drawing in which isillustrated an embodiment thereof.

In this drawing, Figure 1 a side elevation of the rule shown In the closed position. Fig.2 is a top plan view of the same. Fig. 3 is a side elevation showing the device on a larger scale and partly extended. Fig. 4 is a fragmentary top plan view of the device shown on the same scale as in Fig. 3. Fig. 5 is an end elevation looking in the direction of the arrow in Fig. 2, but shown on a larger Fi 6 is a cross section taken on the line 6-6 ig. 2, the parts being shown on a larger scale. Fi 7 Isa perspective view in detail of one of the locking springs shown on a larger scale thanin the other views.

The same reference characters indicate the same parts in all the views. I

Let the numeral 5 designatethe to member; 6 the middle member; and 7 the ottom member of our extension rule as 'illustrated in the drawin three members only being illustrated. T e top memberhas a flat top surface and is graduated adjacent one edge thereof to designate inches or other denominations of measurement. The bottom of this, member is provided with a dove-tailed tongue 8 adapted to engage a counterpart groove 9 formed in the member 6.' The ottom of the latter is provided with a similar .slidable the one upon the other thus making the instrument extensible in the direction of its-length. The top member-which is relatively thin, is reinforced at one extremity as shown at 13 and in this reinforced part is threaded a thumb nut 14 whose lower extremity is provided with an enlargement 14 entering a recess 5 formed in the-bottom of the imember, the said recess being slightly deeper than the enlargement thus allowing the thumb screw to be loosened to permit the two members to slide freely upon each other. The middle member 6 is provided at one extremity with a similar thumb screw 15 which is of the same construction as that just described and is adapted to engage the lower member 7. When these thumb nuts are tightened, the members are locked in the adjusted position. Each member exce t the bottom member is provided with a 100 ing s ring 16 which is secured to the extremity t ereof where the thumb screw is located by means of suitable fastening devices 17. The extremity of each locking spring remote from the fastening devices 17 is provided with a depending portion 18 adapted to enter a recess 19 of the member just below. Each member below the uppermost is provided vith two recesses 19, one near each extremity. One of these recesses isso located that the depending part 18 of the spring engages it when the rule is in the closed position while the other recess 19 is engaged thereby when the rule is fully extend ed, thus making provision for fastening the members together when in either extreme position of adjustment.

The free extremity of each spring 16 is reinforced to engage the recesses 19. The member to which the spring is attached is also provided with a recess 20 (see Fig. 4) adapted to register with one of the recesses 19 in the adjacent member, when the rule is in the closed position. This is necessary since the entire free extremity as well as the depending part is reinforced and in order to allow the free extremity of the fastening spring to enter'the recess 19, the member to which the spring is attached must be provided with a corresponding recess. The free extremity of each spring 16 is also provided with a small knob 21 to facilitatethe out- Ward movement of the sprin for the purpose of releasing the parts to allow them to be freely extended.

The members of the rule are graduated on the top and on one edge thereof. The num bers of these graduated surfaces increase from right to left on the edges of the members and from left to right on the top thereof.

Fromthe foregoing description. the use and operation of our improved device will be readily understood. Assuming that the de-' vice is in the closed position as shown in Fig. 1, if it is desired to extend the same, the free extremities of the locking springs 16 are drawn out of their recesses, thus allowingthe members to slide freely the one upon the other. Under such circumstances it is assumed that the set screws have not been tightened, since while the device is in the closed position there is no necessity for tightenin these screws as the locking s rings 3 16 hold t e parts in the assembled re ation. When the device is extended, however, to the desired position, the set screws are tightened for the purpose of holding it in this position.

These set screws are necessary until one or more members of the rule are fully extended, since the fastening spring of any member is not allowed to enter a recess 19 of another member until one of the members has been extended to the limit of its movement.

Attention is called to the fact that while these rules may be made of any suitable material, it is preferred to make them of steel. It will also be understood that they may be made of any desired number of sections and that these sections may be of any desired length width and thickness.

As shown in the drawing each spring fastening device 16 is preferably secured to the rule member by two screws 17 thus preventing the tendency of the device to turn as might be the case were a single screw em: ployed.

Having thus described our invention, what we claim is:

1. An extension rule composed of a plurality of slidable members arranged one above another, each member except the *lowermost being provided on its top face and near one extremity with a set screw adapted to engage an adjacent member, whereby the various members may be locked in the desired position of adjustment, each member except the lowermost having a spring catch mounted on its edge, each adjacent member having a recess formed in its edge and adapted to be engaged by said spring, the members being graduated and numbered on their upper surface and edges the numbering on the top of the members increasing from left to right and on the edge from right to left, substantially as described.

2. An extensible rule composed of a plurality of slidably connected members arranged one above another, each member except the lowermost being provided on its top face and near one extremity with a set screw adapted to engage the adjacent member, whereby the various members may be locked .in the desired position of adjustment, each member except the lowermost having a spring catch mounted on its edge and each member except the uppermost having a recess formed in its edge and adapted to receive the spring of the adjacent member, substantially as described.

In testimony'whereof we afiix our signatures in resence of two. witnesses.

C IFFORD K. DENMAN.

WILLIAM HARVEY MURPHY. Witnesses:

CARL B. SANBORN,

G. M. HOUSTON. 

